Silencio
So, the Silencing Charm is used in Hogwarts dormitories so that the students can indulge in some quiet wanking or shagging. But is that canon? I don't remember that sort of Silencing Charm existing in the books. (Also, I am not a great fan of it. If drowning out any sounds were that simple, Harry could easily prevent Ron from hearing his nightmares, and IIRC this is something he worries about in OotP.) The only Silencing Charm I can think of is the one cast on living creatures (bullfrogs and ravens) in Flitwick's class. Somehow, the idea of Harry and Ron casting Silencing Charms on each other before wanking each other off is oddly appealing. Has anyone ever used it in a fic? (Doesn't have to be Harry and Ron, though.)